Nearly all vehicle doors having a hinge spring device or other mechanism which retains the door in the full open position until a force is applied thereto to overcome the biasing action of the spring or other mechanism in order to move the door toward the closed position. Nearly all of these hinges use a mechanism which typically consist of metal springs, plastic or metal rollers and detents, and notches in appropriate locations to provide a temporary holding of the door in the open position.
Another common design employs two flat metallic springs or leaf springs. However, such a design lacks spring rate consistency due to various manufacturing limitations and is subject to failure as well as other hinge springs using metal components, by stress cracks forming in the base of the spring where they are bolted or riveted to the vehicle door frame or door. Attempts have been made to eliminate such stress areas in these metallic springs by using a rubber spring pad as a helper spring to enable a lower rate metal spring to be used which is less susceptable to stress cracks. Although this design reduces much of the stress problem, it does not consistently possess the desired spring rate curve.
Another problem with existing hinge spring designs is that in order to control large doors of larger cars and trucks, it is difficult to provide sufficient door cavity sizes and hinge spring components in order to form the metal for the spring with sufficient strength to be able to withstand the forces and repetitions placed thereon.
Various other known prior art door hinge springs are shown in the following patents. U.S. Pat. No. 698,052 discloses a door guide attachment which is attached to the back of a door and has an anti-friction roller adapted to reduce the friction of the guide.
U.S. Pat. No. 2,236,026 discloses the use of a relatively large diameter roller bumper of resilient material in which the axis of the roller bumper is biased by a metal spring during closing of the door. Stop flanges resist movement of the resilient roller in the door closing operation. Although the bumper or roller can be formed of rubber, it must be held in engagement by a metal spring.
U.S. Pat. No. 3,577,840 discloses a self-holding hinge using a detent roller formed of nylon or other plastic or metal material in which the roller is forced over a pair of lips during the closing operation. During the hinge opening or closing, a metal spring is compressed to permit the roller to roll over the detents.
U.S. Pat. No. 4,472,857 discloses a stop device for use with vehicle doors in which a lower roller is spring biased by a helical metal spring against an upper roller, and an arm manufactured with a varying width is forced between the two rollers. The spring of the lower roller resists the insertion of the arm therebetween.
Canadian Pat. No. 558,367 disclosed another hinge device for oven doors which uses a roller which fits into the recess of a lever in a fully opened door position. The lever is resiliently spring biased by a metal spring with the roller being located in a fixed position.
Accordingly, the need has existed for an improved hinge spring construction which eliminates the need for any metallic spring components which will enable the door to move easily to an open position and yet to be retained therein until sufficient force is exerted thereon to move it toward the closed position, the amount of force being variable depending upon the vehicle construction in which the spring is installed.